Dental matrix



(No Model.)

G. LBRUOE.

DENTAL MATRIX.

Patented Jan. 1, 1895.

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UNITED STATES PATENT. Orrion.

GEORGE L. BRUCE, OF BALTIMORE, MARYLAND.

DENTAL MATRIX.

SPECIFICATION forming part of Letters Patent No. 531,833, dated January1, 1895.

Application filed June 12, 1894. Serial No. 14,3 7- N m l- T0 aZZ whomit may concern:

Be it known that I, GEORGE L. BRUCE, a citizen of the United States,residing at Baltimore, in the State of Maryland, have invented certainnew and useful Improvements in Dontal Matrices, of which the followingis a specification.

This invention relates to an improvement in matrices and clamps thereforfor the use of dentists in filling teeth.

The object of the invention is to provide a matrix and clamp of simpleand improved construction.

The invention is illustrated in the accompanying drawings, in which-Figure l is a side View showing the preferred form of dental matrix andclamp with the side plate removed. Fig. 2 is a top or plan view of thesame with plate on. Fig. 3 is a longitudinal section showing a slightmodification. Fig. 4. is a View of the pivoted head.

The letter, A, in the drawings designates a horizontal base-bar having abearing, b, at one end and two lateral or cross slots, c 0', through itat the other end. Ablook, cl, separates the two slots and a metal plate,6, at the side covers the said slots, and a screw, f, passed through theplate and into the block serves to secure the plate. A screw-threadedstem, E, is loose through the bearing, 73, and is provided at its outerend with a thumb nut, E, whereby it is actuated, and at the other endthe stem has a neck, g, to which a head, F,is pivoted, as will behereinafter described. The clamp which is to engage the tooth to befilled, comprises a thin fiat band of resilient metal which forms aloop, j. The two ends, j, j of the clamp pass through the slots, 0, c,in the base-bar, one through each slot, and then extend along the bar.The head, F, is a hollow rectangular shell open at two opposite ends andhaving a pivot hole, It, through it at one end and a. hole, '5, throughits sides at the other end. One open end of this head fits loosely overthe neck, g, of the threaded stem, E, and is pivoted to the neck by apin, h, passed through the hole, It. The two ends, j, 3' of the clampingband connect with the head at the other end and are secured by a pin orrivet, 7), passed through the hole, i.

In Fig. 3 a slight modification is shown. In this instance the end ofthe base-bar, A, has one slot, 0 instead of two slots as in the othercase, and both ends, j, j of the clamping band pass through this singleslot. The clamping band may be endless or have two ends. I

The operation of the device is as follows: The loop, j, of the clamp isengaged to or encircles a tooth to be filled, the nut, E being turned tomove the stem, E, to contract or enlarge the loop to the size required.To tighten the loop on the tooth the nut is turned to draw the stem.This action draws on the band and causes the loop to contract and firmlygrip the tooth.

Having thus described myinvention, what I claim as new, and desire tosecure by Letters Patent, is-

A dental matrix comprising in combination, a base-bar, A, having abearing at one end and one or more lateral slots at the other end; ascrew-threaded stem loose through the bearing and carrying at one end athreaded nut and at the other end a pivoted head; and a clamping bandsecured to the head and passed through the said lateral slot or slots inthe base-bar to form a loop, j, which is to engage a tooth,substantially as described.

In testimony whereof I affix my signature in the presence of twowitnesses.

GEORGE L. BRUCE.

Witnesses:

CHARLES E. MANN, Jr, 0. CALVERT HINES.

